Rigid-flex multilayer boards are known since more than 25 years, yet have not been able to penetrate the commercial market and have always been considered as exotic and expensive. This because rigid-flex PWBs need special design experience, special manufacturing know how and special precautions during assembly and soldering. In the last few years, however, rigid-flex constructions have become increasingly popular, simply because this technology allows an optimal interconnect approach on the system level. The process is accelerated by the rapidly increasing demand for portable electronic devices which have to be packed cost effectively in very small volumes. In addition, the cost for flex materials have come down as a result of the growing volume and number of supplier base, both factors which will further promote the use of this fascinating technology. Even so, the complexity of some rigid-flex MLBs, in particular in areas, like avionics and high-end MIL applications, sometimes reaches extreme levels. Therefore, the aspect of manufacturability has to be designed into the board, in order to avoid drawbacks, like high costs, long lead time and poor reliability. At least in cases, where the designer has low experience in constructing rigid-flex MLBs or when the complexity is above standard, the board supplier should be consulted and asked for inputs and advice. In some exceptional cases, the board designs are so supplier - specific that other suppliers may not be able to process the boards without modifications in scaling factors, build-up or materials. Very well experience in rigid-flex Boards design and manufacturing has company DYCONEX AG (Swiss). More details about Rigid - flexible Multilayer Boards technology you can find here.